Help with angles please.

[bluenose]

Hello folks, I am struggling a bit with my angles and would appreciate a little help if possible please.

I am trying to check the angle settings on my mitre saw and have run into a memory blockage. I particularly want to check the 22.5 degree setting.
Can anyone tell me the easiest way to do this please. I do have a digital angle finder that I can use but I'm not sure how accurate it is. I'm not too sure either how to set this device because it can't be set at 22.5 degrees because then it doesn't marry up with the fence and the blade. It would seem that it has to be set at something like 112 degrees but again my brain isn't remembering what i probably knew 70 or so years ago.
Sorry to appear dim but any guidance will be much appreciated. Thank you.

 

[sunnybob]

full circle =360
half circle = 180
right angle = 90
45 is half of a right, 22.5 is half of 45. Just remember that any right angled mitre joint has to add up to 90.
Cut a 45. then with the sloped edge against the fence, cut another 45 on the same piece. you should have a 22.5

But with a mitre saw, DONT check by just reversing the one cut to see if the wood is straight again. That way lies madness.

Cut a left 45, and then a right 45, put the two together and you should have 90.

 

[marcros]

180 degrees minus your angle. so for 22.5, it is 157.5 degrees.

I would cut 2 pieces at that setting, and check against a 45 degree "square" if you have one. the error will be doubled.

 

[Doug71]

Angle between fence and blade 112.5 degrees or 67.5 degrees depending on which side of blade you are working from.

 

[bluenose]

Thank you chaps, as helpful as ever, thank you all so very much.

It's definitely an age thing you know. It really is so stupid but here's another example, when I'm eating my salad, I can never remember what that grated stuff is that I'm eating, I have to go to the fridge to look at the packaging to remind me that it's coleslaw!!!! :roll:

 

[sunnybob]

With the greatest respect, but if your coleslaw story is true, you should be talking to your doctor at the earliest opportunity.